The present invention relates to apparatus and methods for cutting relatively hard materials by use of high velocity, concentrated fluid jet streams. More particularly, the present invention relates to apparatus and methods for producing channel cuts in relatively hard materials by use of concentrated high velocity, fluid jet streams directed substantially normal to the surface of the material to be cut so that selected material is removed by an erosion process. The present invention is especially useful in performing cutting operations on hard materials such as stone and minerals although it is likewise useful for cutting softer materials such as wood, fabrics and the like. A particularly attractive application for the present invention relates to the use thereof in conjunction with stone quarrying or similar operations.
The problem of how to cut through extremely hard materials has been vexatious to mankind literally for centuries. Structures of various sorts have been constructed entirely from stone readily available in many geographic locations. The inconvenience of locating such stone in appropriately sized blocks for this purpose has required development of various techniques for severing the stone into preferred configurations. Extremely hard stone such as granite is particularly attractive for structural purposes since it provides a more durable resulting structure.
More recently developed materials such as concrete products and the like have found widespread usage as structural elements. The strength and hardness of such materials have likewise presented a cutting problem. Particularly where relatively thick workpieces must be cut, the cutting problem is akin to the problems encountered in quarrying of stone.
A series of developments have been produced for the purpose of cutting through various thick hard elements. For instance, jackhammers, diamond bit drills, blasting powder and the like have been regularly applied to stone quarrying. The resulting product frequently fails to conform to the intended configuration and further involves various inherent safety risks from its usage. Similar hazards as well as additional expense have been entailed in other cutting developments such as burner and wire saws; and these and other devices presently available in many cases have proven to be time-consuming and incapable of accurately forming narrow cuts in stone products.
One arrangement for explosively cutting thick materials has been suggested in U.S. Pat. No. 2,578,243 by Sweetman which employs detonation of an explosive charge to produce a high velocity gas column which is focused to effect a cutting operation. However, such devices are expensive and hazardous in use. It has likewise been suggested that high velocity fluid flow can be used for cutting hard materials as shown in U.S. Pat. No. 2,985,050 by Schwacha wherein a high pressure source of oil is concentrated into a high velocity stream and impinged against the surface of the material to be cut. The cutting qualities of such a procedure have been enhanced by adding abrasive material to the fluidic source. Durable flow concentrating nozzles useful in such high velocity cutting techniques have also been developed such as that shown in U.S. Pat. No. 3,756,106 by Chadwick et al.
Despite the many improvements in hard material cutting processes, there has been a continuing need for means of making relatively narrow, closely controlled cuts through thick sections of hard materials in a rapid manner which is environmentally compatible and employs apparatus which is readily transportable, of minimal cost and safe to operate. The lack of such apparatus and relatively high cost of available cutting apparatus are believed to have been a significant factor in the decline in stone products for structural purposes in recent years.